70 yo F presents to the ED with right arm pain. She reports mechanical fall in her living room, fall onto the right side. No obvious deformity on exam, neurovascular intact. XR as below. What's the diagnosis? (scroll down for answer)

 Answer: Humeral shaft fracture 

-3% of long bone fractures 

-Mechanism: direct blow w/ bending force, FOOSH w/ torsion force

-Humerus is site of muscle insertion for deltoid (anterolateral), pectoralis major (medial intertubercular groove), supraspinatus (greater tuberosity), biceps and triceps (distally)

-Most common associated injury is radial nerve injury: 8-11%, in the lateral intermuscular septum at mid-distal humerus 

Provides sensation over lateral distal upper arm (cutaneous branch) and dorsal thumb 

Test by wrist extension 

-Other injuries include brachial artery and vein, ulnar or median nerves

-Most managed nonoperatively

Coaptation splint, sling, ice, analgesia, ortho referral

Reference: 

Glass C. Upper Arm. In: Sherman SC. eds. Simon’s Emergency Orthopedics, 7e New York, NY: McGraw-Hill; 2014.

Bjoernsen L, Ebinger A. Shoulder and Humerus Injuries. In: Tintinalli JE, Stapczynski J, Ma O, Yealy DM, Meckler GD, Cline DM. eds. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 8e New York, NY: McGraw-Hill; 2016